1. Technical Field
The disclosure relates to a power transmission system and, more particularly, to a power transmission system including a first differential mechanism connected to an engine and a second differential mechanism connected to the first differential mechanism.
2. Description of Related Art
Various power transmission systems have been suggested for a hybrid vehicle that uses an engine and a rotary machine as power sources. For example, International Application Publication No. 2013/114594 describes a power transmission system for a hybrid vehicle. The power transmission system includes a first planetary gear mechanism (hereinafter, referred to as first differential mechanism), a second planetary gear mechanism (hereinafter, referred to as second differential mechanism), a first electric rotary machine, a second electric rotary machine, and a switching device. The first planetary gear mechanism is connected to an internal combustion engine. The second planetary gear mechanism connects the first differential mechanism to drive wheels. The first electric rotary machine is connected to the second differential mechanism. The second electric rotary machine is arranged so as to be able to transmit power to an output element of the second differential mechanism. The switching device consists of two engaging devices (a clutch and a brake) provided in association with the first differential mechanism. The first electric rotary machine and the second electric rotary machine are separately connected to the second differential mechanism.